Technical Field
The instant disclosure relates to a light guiding structure for fingerprint recognizing sheet. In particular, the instant disclosure relates to a light guiding structure for fingerprint recognizing sheet which is applicable to an electronic device, adapted to allow a finger to lie on, and providing illumination during capturing the fingerprint of the finger.
Related Art
Electronic devices, for example, smart phones, notebook computers, flash disks, or even smart door locks, etc., which are provided for storing personal documents, such as mails, photos, or other document files, are required to have unlock and security function.
A conventional electronic device adopted a password authentication method to prevent important information inside the electronic device from being stolen. However, in order to remember the password easily, users may choose their birthday or birthdays of their family members as the passwords. As a result, people with bad intention may get the passwords through various ways, and the important information would be stolen or event exposed to public.
Therefore, in order to improve the security for the electronic device, a fingerprint recognizing function is adopted in the conventional electronic device. One of the advantages of the fingerprint recognizing function is that fingerprint is unique and cannot be replicated, so that the security for electronic devices may be greatly improved. FIG. 1 illustrates a conventional smart phone A. Smart phone is one of the necessities in the daily life. Many users use smart phones to send and receive mails or to store personal document files.
Therefore, a great number of conventional smart phones have the fingerprint recognizing function so as to be capable of performing theftproof function. As shown, the conventional smart phone A includes a fingerprint recognizing region B which allows a user to unlock the smart phone A through fingerprint authentication.
A conventional fingerprint recognizing device includes a circuit board, an image capture device, a light guiding sheet, and LEDs. The image capture device is assembled on the circuit board. The light guiding sheet is disposed above the light guiding sheet. The LEDs are disposed around the periphery of the light guiding sheet, so that the light emitted from the LEDs would be entered into the light guiding sheet. Therefore, when a user put his/her finger on the fingerprint recognizing region B of the fingerprint recognizing device, the brightness of the place where the finger is put on can be increased so as to allow the image capture device to read the fingerprint for fingerprint authentication.
However, for the conventional fingerprint recognizing device, the LEDs are assembled on the circuit board along with the image capture device. Therefore, the manufacturing of the fingerprint recognizing device becomes complicated, and the manufacturing cost is increased.
Another conventional fingerprint recognizing device integrates the image capture device, the light guiding sheet, and the LEDs as an integrated component. And then, the integrated components are secured with the circuit board. Nevertheless, such fingerprint recognizing device is large. As a result, when a smart phone includes the fingerprint recognizing device, the smart phone would be too large to allow a user to hold or carry conveniently.
Consequently, it is an issue that how to make a fingerprint recognizing device which is applicable to an electronic device, adapted to allow a finger to lay on, providing illumination during capturing the fingerprint of the finger, and light weighted.